Pirates right-hander A.J. Burnett took another step forward Sunday morning in his ongoing recovery from a fractured right orbital bone, throwing 54 pitches across four innings in an exhibition game between Double-A Altoona and Triple-A Indianapolis.

According to MLB.com’s Tom Singer, Burnett let up one hit and threw 36 of his 54 pitches for strikes.

The 35-year-old will toss a side session Tuesday before opening the regular season with a rehab start April 6 at Single-A Bradenton. If he avoid setbacks, he should join Pittsburgh’s rotation by the end of April.

Burnett was acquired from the Yankees in February for a couple of minor leaguers and cash considerations. He registered a 5.15 ERA, 1.43 WHIP and 173/83 K/BB ratio in 190 1/3 innings last year for New York.